I have never found the following to ever be worth getting. Am I missing something?
Wheel of pain- Why not just build another Training Ground for faster troop production? And is troop training speed really ever a limiting factor? The limit factor has always been having enough money to build and upkeep troops. You go half the game with never more than a dozen units anyway. Same thing with thralls. Who has ever run short on thralls? You constantly need more gold so you’re building more houses, which also provide thralls and you never run out of thralls before you run out of gold. So that makes both bonuses from the Wheel of Pain worthless because they’re never limiting factors.
Stone walls- Unlike They Are Billions, there is no limit to wall layers. Why not just build more rows of wood walls? Wood is way more plentiful than stone.
Melee infantry- No point to these when defending against waves; ranged units behind walls do all the work. Only need a couple to tank when taking on creeps, but if you have a melee hero then you don’t even need them for that.
Advanced training units: Pikemen, archers, heavy archers, heavy cavalry. Unless there’s something special to them beyond what the numbers say, I don’t see them worth it. For the cost, you get less than you would from javelin throwers. The only thing they’re better in is giving you more bang per thrall, but as mentioned before thralls are never a limiting factor. That seems to be an ongoing thing: the designers thinking that thralls are a valuable limited resource when they might as well not be in the game at all.